وَمَا مُحَمَّدٌ إِلَّا رَسُولٌ قَدۡ خَلَتۡ مِن قَبۡلِهِ ٱلرُّسُلُ ۚ أَفَإِيْن مَّاتَ أَوۡ قُتِلَ ٱنقَلَبۡتُمۡ عَلَىٰٓ أَعۡقَٰبِكُمۡ ۚ وَمَن يَنقَلِبۡ عَلَىٰ عَقِبَيۡهِ فَلَن يَضُرَّ ٱللَّهَ شَيۡـًٔا ۗ وَسَيَجۡزِى ٱللَّهُ ٱلشَّٰكِرِينَ
Muhammad is no more than a messenger: many Were the messenger that passed away before him. If he died or were slain, will ye then Turn back on your heels? If any did turn back on his heels, not the least harm will he do to Allah; but Allah (on the other hand) will swiftly reward those who (serve Him) with gratitude.<br/>
With regard to their being routed, when it was rumoured that the Prophet had been killed and the hypocrites had said to the believers, 'If he has been killed, go back to your [previous] religion', the following was revealed: Muhammad is only a messenger; messengers have passed away before him. Why, if he should die or is slain, like others, will you turn back on your heels, will you return to unbelief (the last statement is the locus of the interrogative of denial, in other words, 'he was not a worshipped being, so that [if he were to die] you should turn back [to your previous religion]'). If any man should turn back on his heels, he will not harm God in any way, but will be harming himself, and God will requite those that are thankful, for His graces by staying firm.